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<head><meta charset="utf-8"><title>Meeting 2021-02-15 · project-portable-simd · Zulip Chat Archive</title></head>
<h2>Stream: <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/index.html">project-portable-simd</a></h2>
<h3>Topic: <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html">Meeting 2021-02-15</a></h3>

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<a name="226428973"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226428973" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Caleb Zulawski <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226428973">(Feb 15 2021 at 20:55)</a>:</h4>
<p>Starts in ~5 minutes, correct?</p>



<a name="226429038"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226429038" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Miguel Raz Guzmán Macedo <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226429038">(Feb 15 2021 at 20:55)</a>:</h4>
<p><span class="user-mention" data-user-id="281757">@Jubilee</span> <span aria-label="octopus" class="emoji emoji-1f419" role="img" title="octopus">:octopus:</span></p>



<a name="226429220"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226429220" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Caleb Zulawski <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226429220">(Feb 15 2021 at 20:57)</a>:</h4>
<p>The only thing I have for today is a bunch of open PRs</p>



<a name="226430870"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226430870" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Edmund Cape <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226430870">(Feb 15 2021 at 21:17)</a>:</h4>
<p>I like the expansion to the glossary.  <br>
I was looking to see how the glossary relates lanes to bitwidth. If it was resolved last week, all good.  If not,  I'm uncertain about how we are relating MaxLaneCount of 64 with bitwidths (a vector term).</p>



<a name="226431139"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226431139" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Caleb Zulawski <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226431139">(Feb 15 2021 at 21:21)</a>:</h4>
<p>I'll have to look at how the glossary describes it, but the general idea is that SimdU8, for example, is generic over lane count.  Without the trait bound it's possible to cause a monomorpisation error by using an invalid size (a non-power-of-two).  The trait also limits to 64 lanes because of the current implementation of bitmasks</p>



<a name="226431190"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226431190" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Caleb Zulawski <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226431190">(Feb 15 2021 at 21:22)</a>:</h4>
<p>I'm not exactly sure what you mean by bit width, do you mean the number of bits per lane, or something else?</p>



<a name="226431294"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226431294" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Edmund Cape <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226431294">(Feb 15 2021 at 21:23)</a>:</h4>
<p>I hope I'm using it the same way the glossary does:  a bitwidth relates to vector size (not lane size).</p>



<a name="226431361"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226431361" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Caleb Zulawski <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226431361">(Feb 15 2021 at 21:24)</a>:</h4>
<p>Like 128 bits for SSE or Neon?</p>



<a name="226431363"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226431363" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Edmund Cape <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226431363">(Feb 15 2021 at 21:24)</a>:</h4>
<blockquote>
<p><strong>Bit Widths:</strong> When talking about SIMD, the bit widths used are the bit size of the vectors involved, <em>not</em> the individual elements. So "128-bit SIMD" has 128-bit vectors</p>
</blockquote>



<a name="226431428"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226431428" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226431428">(Feb 15 2021 at 21:25)</a>:</h4>
<p>hello!</p>



<a name="226431441"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226431441" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226431441">(Feb 15 2021 at 21:25)</a>:</h4>
<p>oh, I thought we were officially starting these at 13:30 lol.</p>



<a name="226431510"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226431510" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Caleb Zulawski <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226431510">(Feb 15 2021 at 21:26)</a>:</h4>
<p>Ah gotcha.  So the maximum lane count is only tangentially related to bit width.  We picked 64 because that allows you to represent at least a u8x64 AVX-512 vector, which is our largest supported bit width  at the moment.</p>



<a name="226431571"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226431571" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Caleb Zulawski <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226431571">(Feb 15 2021 at 21:27)</a>:</h4>
<p><span class="user-mention" data-user-id="281757">@Jubilee</span> which time zone? I thought we were sticking with this but I could be wrong</p>



<a name="226431585"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226431585" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226431585">(Feb 15 2021 at 21:27)</a>:</h4>
<p>Pacific. So I mean like right now.</p>



<a name="226431610"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226431610" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Caleb Zulawski <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226431610">(Feb 15 2021 at 21:28)</a>:</h4>
<p>Oh okay, so pushed back half an hour? That works too.  Well we're here!</p>



<a name="226431650"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226431650" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Edmund Cape <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226431650">(Feb 15 2021 at 21:28)</a>:</h4>
<p>Ah. That makes sense: u8 x 64 = max supported vector size = 512 bits.</p>



<a name="226431687"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226431687" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226431687">(Feb 15 2021 at 21:28)</a>:</h4>
<p>Yeah, our lane maximum is a logical, compiler limitation rather than a hardware one, but incidentally we expect the hardware to want up to 64, so we're going with that.</p>



<a name="226431729"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226431729" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Caleb Zulawski <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226431729">(Feb 15 2021 at 21:29)</a>:</h4>
<p><span class="user-mention" data-user-id="388128">@Edmund Cape</span> it's possible to do something much larger, such as a u128x64 (which gets lowered to a whole bunch of vectors), so 64 was intended to ensure we could support at least 512 bits.  We could have done 128 lanes as well but it wasn't necessary</p>



<a name="226431830"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226431830" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Edmund Cape <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226431830">(Feb 15 2021 at 21:30)</a>:</h4>
<p>Got it. That 64 number is an overloaded number :)) I was thinking in terms of 64-bit.</p>



<a name="226431878"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226431878" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226431878">(Feb 15 2021 at 21:30)</a>:</h4>
<p>POWERS OF TWO!</p>



<a name="226431879"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226431879" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Edmund Cape <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226431879">(Feb 15 2021 at 21:30)</a>:</h4>
<p>Does that mean we have a minimum lane size of 8-bit?</p>



<a name="226431893"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226431893" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Caleb Zulawski <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226431893">(Feb 15 2021 at 21:31)</a>:</h4>
<p>Yep</p>



<a name="226431896"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226431896" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226431896">(Feb 15 2021 at 21:31)</a>:</h4>
<p>Effectively.</p>



<a name="226431909"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226431909" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226431909">(Feb 15 2021 at 21:31)</a>:</h4>
<p>Rust doesn't really support sub-byte addressing.</p>



<a name="226431928"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226431928" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Edmund Cape <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226431928">(Feb 15 2021 at 21:31)</a>:</h4>
<p>Do we specify that min-lane-size somewhere?</p>



<a name="226431934"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226431934" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Caleb Zulawski <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226431934">(Feb 15 2021 at 21:31)</a>:</h4>
<p>The bitmasks are technically vectors of 1 bit integers, but that's a special case</p>



<a name="226432001"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226432001" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Edmund Cape <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226432001">(Feb 15 2021 at 21:32)</a>:</h4>
<p>Yes and no to the sub-byte addressing.  There are SIMD operations where I have worked on 4-bits</p>



<a name="226432002"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226432002" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226432002">(Feb 15 2021 at 21:32)</a>:</h4>
<p>We can interact with single bits by treating them as a bitfield embedded in a number, yes.<br>
Hmm, MinLaneWidth? No, we just don't provide any types that could use less. Since we control the types we're exposing directly, we're fine.</p>



<a name="226432007"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226432007" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Caleb Zulawski <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226432007">(Feb 15 2021 at 21:32)</a>:</h4>
<p>It may need some updating, but I think it says somewhere that vectors are over rust primitive types</p>



<a name="226432077"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226432077" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226432077">(Feb 15 2021 at 21:33)</a>:</h4>
<p><span class="user-mention" data-user-id="388128">@Edmund Cape</span> Have you done that with a Rust API, or with Intel intrinsics?</p>



<a name="226432126"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226432126" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226432126">(Feb 15 2021 at 21:33)</a>:</h4>
<p>I am <strong>very</strong> interested if the former is the case. <span aria-label="eyes" class="emoji emoji-1f440" role="img" title="eyes">:eyes:</span></p>



<a name="226432196"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226432196" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Edmund Cape <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226432196">(Feb 15 2021 at 21:34)</a>:</h4>
<p>All good.  I was just thinking that the logic for the Max64Lane constant because of the 512-bit max vector size, by definition means a min lane size... implied vs explicit.</p>



<a name="226432326"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226432326" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Caleb Zulawski <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226432326">(Feb 15 2021 at 21:36)</a>:</h4>
<p>If somehow rust added support for u4, there's nothing about the lane restriction that would prevent us from implementing it</p>



<a name="226432354"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226432354" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226432354">(Feb 15 2021 at 21:36)</a>:</h4>
<p>Correct.<br>
We might up the lane max too, if we felt it was warranted.</p>



<a name="226432355"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226432355" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Edmund Cape <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226432355">(Feb 15 2021 at 21:36)</a>:</h4>
<p><span class="user-mention" data-user-id="281757">@Jubilee</span> To be quite honest, I'm not sure! :)) what I mean by that is that I believe I was using a combination.  I suspect the 4-bit work was using the intrinsics API.</p>



<a name="226432365"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226432365" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226432365">(Feb 15 2021 at 21:36)</a>:</h4>
<p>Okay. ^_^</p>



<a name="226432447"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226432447" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226432447">(Feb 15 2021 at 21:38)</a>:</h4>
<p>Rust has a deeply embedded logical memory model that operates on 1 or more octet bytes at a time, that doesn't mean it can't be hacked to do less than 8 bits at a time, it just means it has to express those operations in terms of byte-level operations.</p>



<a name="226432457"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226432457" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Edmund Cape <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226432457">(Feb 15 2021 at 21:38)</a>:</h4>
<p>The way I see you all talking about it, I'm sure it was as you all describe.<br>
Conceptually, the line between Rust and the intrinsics is still a bit muddled for me.</p>



<a name="226432510"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226432510" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Edmund Cape <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226432510">(Feb 15 2021 at 21:39)</a>:</h4>
<p>Will users of this API ever bounce in and out of using intrinsics?</p>



<a name="226432527"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226432527" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Caleb Zulawski <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226432527">(Feb 15 2021 at 21:39)</a>:</h4>
<p>The goal is to minimize needing to do that, but making it easy to do it if you need to</p>



<a name="226432530"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226432530" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226432530">(Feb 15 2021 at 21:39)</a>:</h4>
<p>We're kind of assuming yes.</p>



<a name="226432635"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226432635" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Edmund Cape <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226432635">(Feb 15 2021 at 21:40)</a>:</h4>
<p>In a worse case, a simple note in the glossary explaining the logic is likely "way good enough".</p>



<a name="226432682"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226432682" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226432682">(Feb 15 2021 at 21:40)</a>:</h4>
<p>but that it wouldn't be the main point... most people just want the abstract level. But a big enough minority will want the optimization powers of using explicit intrinsics, and we need to offer interop with those so they don't have to have that be their ENTIRE program.</p>
<p>Oh yeah, I have more to go into the guide, I just wanted to make the glossary expansion thing its own PR.</p>



<a name="226432801"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226432801" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226432801">(Feb 15 2021 at 21:43)</a>:</h4>
<p><span class="user-mention" data-user-id="312331">@Caleb Zulawski</span> I haven't reviewed the proptest branch extensively, but it looks like we can merge our PRs? I'm gonna squash my commits real quick.</p>



<a name="226432824"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226432824" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Caleb Zulawski <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226432824">(Feb 15 2021 at 21:44)</a>:</h4>
<p>Yeah, I think they're all good to merge</p>



<a name="226432893"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226432893" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Caleb Zulawski <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226432893">(Feb 15 2021 at 21:44)</a>:</h4>
<p>I didn't actually change the existence of any tests, just changed how they're done (hopefully)</p>



<a name="226433028"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226433028" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226433028">(Feb 15 2021 at 21:46)</a>:</h4>
<p>Hmm.<br>
OK, then I will review proptest again and merge it when I have given it another pass.<br>
I reviewed a lot of float intrinsics and have determined that a LOT of them are dependent on like<br>
resolving our "situation" with regards to libm and floats, even the seemingly simple ones.</p>



<a name="226433058"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226433058" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226433058">(Feb 15 2021 at 21:47)</a>:</h4>
<p>Merging the lane limit PR now, if we're good on that?</p>



<a name="226433195"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226433195" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Caleb Zulawski <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226433195">(Feb 15 2021 at 21:49)</a>:</h4>
<p>Agreed wrt floats</p>



<a name="226433200"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226433200" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226433200">(Feb 15 2021 at 21:49)</a>:</h4>
<p>And my glossary PR should be good to go.<br>
I have one and a half other docs things like, waiting in the wings. ^^; Well, mostly on me redrafting them.</p>



<a name="226433304"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226433304" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Miguel Raz Guzmán Macedo <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226433304">(Feb 15 2021 at 21:50)</a>:</h4>
<p>I'm not a designer person, but just having a chart of what all the different terms mean + pictures would probs help immensely.</p>



<a name="226433307"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226433307" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226433307">(Feb 15 2021 at 21:50)</a>:</h4>
<p>I identified a few <code>platform-intrinsics</code> like <code>simd_fma</code> (which would be in as <code>mul_add</code>) which BETTER NOT resolve to calls to libm though, and I think we should make sure we've found those where they're already in, surfaced them, and commit them.</p>



<a name="226433310"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226433310" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226433310">(Feb 15 2021 at 21:51)</a>:</h4>
<p><span class="user-mention" data-user-id="246783">@Miguel Raz Guzmán Macedo</span> what kind of chart</p>



<a name="226433315"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226433315" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226433315">(Feb 15 2021 at 21:51)</a>:</h4>
<p>and/or what kind of pictures?</p>



<a name="226433396"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226433396" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Miguel Raz Guzmán Macedo <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226433396">(Feb 15 2021 at 21:52)</a>:</h4>
<p>Something like this, but with lanewidths, vector, and scalar tagged <a href="https://cheats.rs/#numeric-types-ref">https://cheats.rs/#numeric-types-ref</a></p>



<a name="226433398"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226433398" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226433398">(Feb 15 2021 at 21:52)</a>:</h4>
<p>like, general, vague waving in a direction is fine, just "chart" and "pictures" conjure... blankness</p>



<a name="226433404"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226433404" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226433404">(Feb 15 2021 at 21:52)</a>:</h4>
<p>aha</p>



<a name="226433422"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226433422" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226433422">(Feb 15 2021 at 21:52)</a>:</h4>
<p>Yes, we can do that.</p>



<a name="226433465"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226433465" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Miguel Raz Guzmán Macedo <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226433465">(Feb 15 2021 at 21:53)</a>:</h4>
<p>"Look at this memory - it has a lanesize of 128 bits, but each vector is of 32 bit floats."</p>



<a name="226433496"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226433496" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226433496">(Feb 15 2021 at 21:54)</a>:</h4>
<p>vector width of 128, lane width of 32 bits</p>



<a name="226433526"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226433526" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Miguel Raz Guzmán Macedo <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226433526">(Feb 15 2021 at 21:54)</a>:</h4>
<p>(deleted)</p>



<a name="226433542"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226433542" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226433542">(Feb 15 2021 at 21:54)</a>:</h4>
<p>lol, no, it's good, you instantly demonstrated why we need it.</p>



<a name="226433579"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226433579" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226433579">(Feb 15 2021 at 21:55)</a>:</h4>
<p>nooo, don't delete it. ^_^</p>



<a name="226433592"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226433592" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226433592">(Feb 15 2021 at 21:55)</a>:</h4>
<p>It's okay~!</p>



<a name="226433607"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226433607" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Miguel Raz Guzmán Macedo <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226433607">(Feb 15 2021 at 21:55)</a>:</h4>
<p>Then there is an "a vertical operation is between the matching lanes of different SIMD vectors, and a horizontal operation is inside the same SIMD vector"</p>



<a name="226433668"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226433668" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226433668">(Feb 15 2021 at 21:56)</a>:</h4>
<p>Right.<br>
<span class="user-mention" data-user-id="312331">@Caleb Zulawski</span> Would you like to do the honors re: <a href="https://github.com/rust-lang/rust/issues/73">#73</a><br>
I feel silly about merging my own PR. :^)</p>



<a name="226433673"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226433673" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226433673">(Feb 15 2021 at 21:56)</a>:</h4>
<p><span class="user-mention" data-user-id="246783">@Miguel Raz Guzmán Macedo</span> Can you file that as an issue, please?</p>



<a name="226433685"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226433685" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Miguel Raz Guzmán Macedo <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226433685">(Feb 15 2021 at 21:56)</a>:</h4>
<p>Aye aye Cap'n.</p>



<a name="226434111"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226434111" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Caleb Zulawski <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226434111">(Feb 15 2021 at 22:00)</a>:</h4>
<p><span class="user-mention" data-user-id="281757">@Jubilee</span> done</p>



<a name="226434179"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226434179" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226434179">(Feb 15 2021 at 22:01)</a>:</h4>
<p>Thank you!</p>



<a name="226434221"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226434221" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Miguel Raz Guzmán Macedo <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226434221">(Feb 15 2021 at 22:01)</a>:</h4>
<p>Same</p>



<a name="226434326"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226434326" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Caleb Zulawski <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226434326">(Feb 15 2021 at 22:01)</a>:</h4>
<p>I don't mind merging my own as long as all of the reviewers approve or we discuss it</p>



<a name="226434603"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226434603" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Miguel Raz Guzmán Macedo <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226434603">(Feb 15 2021 at 22:02)</a>:</h4>
<p>I liked the proptests ! &lt;3</p>



<a name="226434604"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226434604" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226434604">(Feb 15 2021 at 22:02)</a>:</h4>
<p>I mostly feel a little odd if I've diffed it and I'm not sure if people approve or just didn't notice. :^) <br>
Should we have a slightly more formal merging policy?</p>



<a name="226434699"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226434699" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Miguel Raz Guzmán Macedo <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226434699">(Feb 15 2021 at 22:03)</a>:</h4>
<p>I'm not sure if when working on the crate, there is a way to opt out of them with some <code>cargo -- stuff?</code></p>



<a name="226434728"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226434728" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226434728">(Feb 15 2021 at 22:03)</a>:</h4>
<p>I think "by consensus" has been the policy effectively which is good but slightly more formal signaling on consensus maybe.</p>



<a name="226434748"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226434748" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226434748">(Feb 15 2021 at 22:03)</a>:</h4>
<p>there should be a way to run only one test?</p>



<a name="226435169"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226435169" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226435169">(Feb 15 2021 at 22:06)</a>:</h4>
<p>It's something like <code>cargo test path/to/test</code></p>



<a name="226435312"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226435312" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Caleb Zulawski <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226435312">(Feb 15 2021 at 22:07)</a>:</h4>
<p>Yeah perhaps we need a more formal policy.  Though I think to some extent our PRs are more of a courtesy, if you look at the main rust repo you only need one approval</p>



<a name="226435389"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226435389" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226435389">(Feb 15 2021 at 22:07)</a>:</h4>
<p>one formal approval from who. :^)</p>



<a name="226435392"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226435392" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Miguel Raz Guzmán Macedo <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226435392">(Feb 15 2021 at 22:07)</a>:</h4>
<p>Whoah, I thought the Rust people had some big public implementation pipeline with proposals.</p>



<a name="226435448"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226435448" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Miguel Raz Guzmán Macedo <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226435448">(Feb 15 2021 at 22:08)</a>:</h4>
<p>And a well defined state-machine and stuff.</p>



<a name="226435471"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226435471" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226435471">(Feb 15 2021 at 22:08)</a>:</h4>
<p>LOL</p>



<a name="226435480"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226435480" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226435480">(Feb 15 2021 at 22:08)</a>:</h4>
<p>no we're anarchists.</p>



<a name="226435496"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226435496" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Miguel Raz Guzmán Macedo <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226435496">(Feb 15 2021 at 22:08)</a>:</h4>
<p><span aria-label="octopus" class="emoji emoji-1f419" role="img" title="octopus">:octopus:</span></p>



<a name="226435523"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226435523" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226435523">(Feb 15 2021 at 22:08)</a>:</h4>
<p>I mean, yes, we have feature flags and RFCs and issues and such.</p>



<a name="226435651"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226435651" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Caleb Zulawski <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226435651">(Feb 15 2021 at 22:09)</a>:</h4>
<p>I think perhaps we just need to establish who has merge permissions (which we already have done de facto)</p>



<a name="226435704"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226435704" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Caleb Zulawski <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226435704">(Feb 15 2021 at 22:09)</a>:</h4>
<p>Once we're in nightly I think we for the most part follow the same rules as any other feature</p>



<a name="226436200"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226436200" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226436200">(Feb 15 2021 at 22:12)</a>:</h4>
<p>Yeah.<br>
Oh, and proptest needs a rebase because... git is bad.</p>



<a name="226436443"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226436443" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226436443">(Feb 15 2021 at 22:14)</a>:</h4>
<p>My apologies. <span aria-label="pray" class="emoji emoji-1f64f" role="img" title="pray">:pray:</span></p>



<a name="226436479"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226436479" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Caleb Zulawski <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226436479">(Feb 15 2021 at 22:14)</a>:</h4>
<p>Ha. I'll take care of it later today.</p>



<a name="226436553"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226436553" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Caleb Zulawski <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226436553">(Feb 15 2021 at 22:15)</a>:</h4>
<p>Once I've done that feel free to merge it once you've looked it over</p>



<a name="226436602"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226436602" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226436602">(Feb 15 2021 at 22:15)</a>:</h4>
<p>yes!</p>



<a name="226436844"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226436844" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Caleb Zulawski <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226436844">(Feb 15 2021 at 22:17)</a>:</h4>
<p>As far as future work goes I've started with the floating point classification functions</p>



<a name="226436862"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226436862" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226436862">(Feb 15 2021 at 22:17)</a>:</h4>
<p>Oh nice.</p>



<a name="226436869"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226436869" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Caleb Zulawski <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226436869">(Feb 15 2021 at 22:17)</a>:</h4>
<p>I figure those are useful to someone...</p>



<a name="226436873"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226436873" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226436873">(Feb 15 2021 at 22:17)</a>:</h4>
<p>&lt;_&lt;;;</p>



<a name="226436884"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226436884" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226436884">(Feb 15 2021 at 22:18)</a>:</h4>
<p>I keep meaning to open a PR for mul_add but then I go "oh I should see if I can add other float functions to this"<br>
and then I keep finding another float function that calls to libm</p>



<a name="226436928"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226436928" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226436928">(Feb 15 2021 at 22:18)</a>:</h4>
<p>And then I deep sigh.</p>



<a name="226436934"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226436934" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Miguel Raz Guzmán Macedo <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226436934">(Feb 15 2021 at 22:18)</a>:</h4>
<p>mul_add is a huge perk, that would be nice to have.</p>



<a name="226436949"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226436949" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226436949">(Feb 15 2021 at 22:18)</a>:</h4>
<p>Yeah, I just am saying that to convince myself that it's not a sin to open a PR with one new function. :^)</p>



<a name="226436970"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226436970" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226436970">(Feb 15 2021 at 22:19)</a>:</h4>
<p>maybe if the function was <code>sin()</code></p>



<a name="226437035"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226437035" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Lokathor <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226437035">(Feb 15 2021 at 22:20)</a>:</h4>
<p><em>arrives late</em></p>



<a name="226437403"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226437403" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226437403">(Feb 15 2021 at 22:24)</a>:</h4>
<p>oh silly almost bikeshed painting level question:<br>
since all our ops are Wrapping implicitly<br>
should we even bother adding the <code>wrapping_*</code> functions?<br>
pros: more seamless transition I guess?<br>
cons: they're just API clutter at that point</p>



<a name="226437640"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226437640" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Caleb Zulawski <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226437640">(Feb 15 2021 at 22:27)</a>:</h4>
<p>Oh yeah, looking over my old issues I noticed that. No I don't think we should</p>



<a name="226437666"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226437666" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Caleb Zulawski <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226437666">(Feb 15 2021 at 22:27)</a>:</h4>
<p>I think we only need the checked variants</p>



<a name="226437710"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226437710" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226437710">(Feb 15 2021 at 22:28)</a>:</h4>
<p>and saturating ofc.</p>



<a name="226437717"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226437717" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Caleb Zulawski <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226437717">(Feb 15 2021 at 22:28)</a>:</h4>
<p>Right</p>



<a name="226437720"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226437720" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226437720">(Feb 15 2021 at 22:28)</a>:</h4>
<p>And yeah I raised it because I'm mildly against, it misleads people into thinking they need the <code>wrapping_*</code> functions.</p>



<a name="226437994"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226437994" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Miguel Raz Guzmán Macedo <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226437994">(Feb 15 2021 at 22:32)</a>:</h4>
<p><span class="user-mention" data-user-id="281757">@Jubilee</span> this should work right?</p>
<div class="codehilite" data-code-language="Rust"><pre><span></span><code><span class="kd">let</span><span class="w"> </span><span class="n">v</span><span class="w"> </span><span class="o">=</span><span class="w"> </span><span class="n">SIMDI32</span><span class="o">&lt;</span><span class="mi">128</span><span class="o">&gt;</span><span class="p">([</span><span class="mi">1</span><span class="k">i32</span><span class="p">,</span><span class="w"> </span><span class="mi">2</span><span class="k">i32</span><span class="p">,</span><span class="w"> </span><span class="mi">3</span><span class="k">i32</span><span class="p">,</span><span class="w"> </span><span class="mi">4</span><span class="k">i32</span><span class="p">]);</span><span class="w"></span>
</code></pre></div>



<a name="226438003"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226438003" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Lokathor <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226438003">(Feb 15 2021 at 22:32)</a>:</h4>
<p>isn't it &lt;4&gt; ?</p>



<a name="226438017"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226438017" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226438017">(Feb 15 2021 at 22:32)</a>:</h4>
<p><code>SimdI32&lt;4&gt;</code></p>



<a name="226438045"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226438045" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Miguel Raz Guzmán Macedo <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226438045">(Feb 15 2021 at 22:33)</a>:</h4>
<p>Ah, gotcha.</p>



<a name="226438068"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226438068" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226438068">(Feb 15 2021 at 22:33)</a>:</h4>
<p>and... uh, it's written slightly differently and my brain is freezing up on how.</p>



<a name="226438071"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226438071" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Miguel Raz Guzmán Macedo <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226438071">(Feb 15 2021 at 22:33)</a>:</h4>
<p>Is this not too shabby?<br>
<a href="https://imgur.com/2vqE1XB.png">https://imgur.com/2vqE1XB.png</a></p>
<div class="message_inline_image"><a href="https://imgur.com/2vqE1XB.png"><img src="https://imgur.com/2vqE1XB.png"></a></div>



<a name="226438128"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226438128" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226438128">(Feb 15 2021 at 22:34)</a>:</h4>
<p>Sure.</p>



<a name="226438138"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226438138" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Caleb Zulawski <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226438138">(Feb 15 2021 at 22:34)</a>:</h4>
<p><span class="user-mention" data-user-id="246783">@Miguel Raz Guzmán Macedo</span> that wouldn't work since the inner member is private, but you could use the Into trait</p>



<a name="226438179"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226438179" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226438179">(Feb 15 2021 at 22:35)</a>:</h4>
<p>serious question: does the inner member need to be private? It's just a number.</p>



<a name="226438200"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226438200" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226438200">(Feb 15 2021 at 22:35)</a>:</h4>
<p>well, number<strong>s</strong>. I forget why we need it to be private.</p>



<a name="226438244"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226438244" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226438244">(Feb 15 2021 at 22:36)</a>:</h4>
<p>I think there was actually a reason.</p>



<a name="226438302"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226438302" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Lokathor <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226438302">(Feb 15 2021 at 22:37)</a>:</h4>
<p>i'd make the outside green, and the inside boxes blue, so that they match the text coloration</p>



<a name="226452063"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226452063" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Lokathor <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226452063">(Feb 15 2021 at 22:38)</a>:</h4>
<p>and the 4 should maybe be just be called "lane count"</p>



<a name="226452075"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226452075" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Caleb Zulawski <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226452075">(Feb 15 2021 at 22:38)</a>:</h4>
<p>I don't think it needs to be, but I do think it makes sense to make it very explicit if you're using an array or a slice instead of a simd operation?</p>



<a name="226452111"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226452111" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226452111">(Feb 15 2021 at 22:39)</a>:</h4>
<p>Also, I know it's UB to do signed integer overflow in C/C++, but is it UB to do so with SIMD intrinsics?</p>



<a name="226452288"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226452288" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Miguel Raz Guzmán Macedo <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226452288">(Feb 15 2021 at 22:41)</a>:</h4>
<div class="message_inline_image"><a href="https://imgur.com/pRGzCst.png"><img src="https://imgur.com/pRGzCst.png"></a></div>



<a name="226452296"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226452296" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Caleb Zulawski <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226452296">(Feb 15 2021 at 22:41)</a>:</h4>
<p>I think because rust specifies that integers are twos compliment it's not UB in rust?</p>



<a name="226452377"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226452377" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226452377">(Feb 15 2021 at 22:42)</a>:</h4>
<p>Oh I meant C/C++ specifically.</p>



<a name="226452380"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226452380" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Caleb Zulawski <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226452380">(Feb 15 2021 at 22:42)</a>:</h4>
<p>LLVM's add instruction performs two's compliment overflow</p>



<a name="226452381"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226452381" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Miguel Raz Guzmán Macedo <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226452381">(Feb 15 2021 at 22:42)</a>:</h4>
<div class="message_inline_image"><a href="https://imgur.com/OjVAj1T.png"><img src="https://imgur.com/OjVAj1T.png"></a></div>



<a name="226452385"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226452385" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226452385">(Feb 15 2021 at 22:42)</a>:</h4>
<p>I know thatit's not in Rust.</p>



<a name="226452412"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226452412" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Caleb Zulawski <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226452412">(Feb 15 2021 at 22:43)</a>:</h4>
<p>Oh, no you can use _mm_add_epi32 or whatever to do overflow and that's fine</p>



<a name="226452511"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226452511" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Caleb Zulawski <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226452511">(Feb 15 2021 at 22:44)</a>:</h4>
<p>(a compiler could provide an Intel add intrinsic for a single integer that does it as well)</p>



<a name="226452562"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226452562" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226452562">(Feb 15 2021 at 22:45)</a>:</h4>
<p>Oh OK, so in SIMD intrinsics, basically, you're never given the "overflow is UB" catch anyways</p>



<a name="226452680"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226452680" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Caleb Zulawski <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226452680">(Feb 15 2021 at 22:46)</a>:</h4>
<p>Yeah. Well maybe on some one's compliment system <span aria-label="smiling devil" class="emoji emoji-1f608" role="img" title="smiling devil">:smiling_devil:</span></p>



<a name="226452701"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226452701" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Caleb Zulawski <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226452701">(Feb 15 2021 at 22:46)</a>:</h4>
<p>Though I suppose there you'd just have different overflow semantics</p>



<a name="226453021"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226453021" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Miguel Raz Guzmán Macedo <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226453021">(Feb 15 2021 at 22:50)</a>:</h4>
<p>Here's the ppt in case anyone wants to bikeshed my visual design <a href="https://docs.google.com/presentation/d/1UZAQThA0TwdHalYNLLGJOxe0BV-drCF8QavI3tl5Q68/edit?usp=sharing">https://docs.google.com/presentation/d/1UZAQThA0TwdHalYNLLGJOxe0BV-drCF8QavI3tl5Q68/edit?usp=sharing</a></p>



<a name="226453169"></a>
<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226453169" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226453169">(Feb 15 2021 at 22:53)</a>:</h4>
<p>Just wanted to add that in here. <a href="https://github.com/rust-lang/stdsimd/issues/56#issuecomment-779475737">https://github.com/rust-lang/stdsimd/issues/56#issuecomment-779475737</a><br>
Anyways, then I think we are good for today. We still have a bit of work before we should launch into landing on nightly, I think, but we're making good progress.<br>
<span class="user-mention" data-user-id="246783">@Miguel Raz Guzmán Macedo</span> Nice!</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226453338" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Miguel Raz Guzmán Macedo <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226453338">(Feb 15 2021 at 22:56)</a>:</h4>
<p>ermahgerd it's tarcieri!</p>



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<h4><a href="https://rust-lang.zulipchat.com#narrow/stream/257879-project-portable-simd/topic/Meeting%202021-02-15/near/226453740" class="zl"><img src="https://rust-lang.github.io/zulip_archive/assets/img/zulip.svg" alt="view this post on Zulip" style="width:20px;height:20px;"></a> Jubilee <a href="https://rust-lang.github.io/zulip_archive/stream/257879-project-portable-simd/topic/Meeting.202021-02-15.html#226453740">(Feb 15 2021 at 23:03)</a>:</h4>
<p>Thank you all for coming! <span aria-label="sparkling heart" class="emoji emoji-1f496" role="img" title="sparkling heart">:sparkling_heart:</span></p>



<hr><p>Last updated: Aug 07 2021 at 22:04 UTC</p>
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